Various types of cameras have recently been proposed which are provided with a barrier mechanism on the front of a photographic lens for the purpose of protecting it. However, they have a disadvantage with respect to operational properties because such a barrier portion is generally independent and is manually driven before and after a photograph is taken.
In order to remove the above-described disadvantage, a method has been considered in which a motor exclusively used for driving a barrier is provided so as to automatically drive the barrier with an interlocking release. However, this method has the disadvantage in that many component parts are required and thus the size and cost of a camera are increased. In addition, in a camera having a lens with two or more focal points such as a telephoto lens or wide angle lens, this method has a disadvantage in that a shutter is moved in the direction of an optical axis and thus any interlocking mechanism provided between a barrier portion and a body portion necessarily becomes complicated.
In a camera having separate motors used respectively for driving a lens and a barrier, the driving of the barrier in the driving range of the lens consumes an excessive amount of current and thus causes an increase in the cost of the associated power circuit or motor-driven circuit.
The present invention has been achieved with a view to solving the above-described disadvantages, and it is an object of the present invention to provide a motor-driven shutter for a camera having a barrier which is driven without the need for a separate motor to be provided for the barrier.